I once found an Alexander McQueen suit jacket in Help The Aged for £4.50. It was my interview jacket for years. I never got why someone would bother paying that much for a suit until I realised how well it fitted - it was designed for an actual figure rather than fitting like a school blazer with my norks awkwardly squished underneath.
I went to a temp agency when I was last unemployed and was told that in the City I'd be expected to wear a suit and heels - god knows how much it would cost to get stuff that actually fits me properly if I was doing that every day. I have size 9 feet for a start. I always wanted to get a Bravissimo shirt when I had to wear office-y clothing every day but I couldn't afford it at the time - luckily those shirts that fastened with hooks and eyes were popular then.